1. Field of the Invention
The present invention relates to a data and power transmitting cable system, particularly to a data and power transmitting cable system which improves on standard Universal Serial Bus and IEEE1394 cables by allowing for additional transmitted power.
2. Description of Related Art
Cables for connecting a computer with peripheral devices, like a keyboard, a mouse, a scanner or an external data storage device, have been increasingly standardized. For transmission speeds or data rates below 12 Mbits per second, Universal Serial Bus (USB) cables have increasingly been used. For higher data rates, of 100 Mbits per second and above, IEEE1394 cables have more and more come into use.
As shown in FIG. 22-24, a USB cable has an A connector 10, a first cable 15 and a B connector 20. The A connector has four metal pins, designated 1, 2, 3 and 4, used as Vbus, -Data, +Data and Ground pins, respectively. Accordingly, the B connector has four metal pins, designated 1a, 2a, 3aand 4a, used as Vbus, -Data, +Data and Ground pins, respectively. The first cable 15 has four metal wires, a first, a second, a third and a fourth wire. The first wire connects pins 1 and 1a, the second wire connects pins 2 and 2a, the third wire connects pins 3 and 3a, and the fourth wire connects pins 4 and 4a. The first and fourth wires form a power supply line, and the second and third wires are used for data transmission.
IEEE1394 cables (not shown) look different from USB cables. IEEE1394 cables have another two wires for data and thus have a total of six wires, two wires forming a power circuit and four wires being used for data transmission.
Electric voltages and currents in both USB cables and IEEE1394 cables are clearly defined. USB cables carry a voltage of +5V and a maximum current of 0.5 A. IEEE1394 cables carry a voltage of +8V to +40V and a maximum current of 1.5 A.
Devices connecting via a cable either have an extra power supply of their own or are supplied with power by the cable. Extra power supplies are mainly used for devices with relatively high power consumption, like scanners or storage devices. Devices with low power consumption, like keyboards or mouses, rely on power supplied by the cable.
Devices consuming more power than is admitted through the cable need installation of an extra power supply. As shown in FIGS. 25-27, a device 25 has a USB interface port 23 with four pins 1b, 2b, 3b, 4b which are respectively connected to the pins 1a, 2a, 3a, 4a of the B connector 20 of the USB cable. Furthermore, the device 25 has a power input jack 24 with two pins 5, 6. A power adapter 17 is plugged into the power input jack 24, connecting to the pins 5, 6 and supplying the device 25 with power. The power adapter 17 in turn is connected with a wall outlet, receiving power therefrom. If the device 25 needs just a little more power than is admitted through the USB cable, it is desirable to have another way to supply the device 25 than the extra power supply shown in FIGS. 25-27.